Field of the Invention
The present invention relates to an image capturing apparatus, a control method thereof, and a storage medium, and particularly to an image processing technology using high dynamic range (HDR) compositing.
Description of the Related Art
In recent years, there exist image capturing apparatuses equipped with various image capturing technologies. A high dynamic range (HDR) compositing technology is known which makes it possible to acquire an image having a broader dynamic range than a dynamic range acquired in one photographing operation by compositing a plurality of images acquired by photographing the same scene with varied exposure amounts. It is possible to acquire, by using the HDR compositing technology, an image in which blown-out highlights and crushed blacks in the shot image are suppressed.
A technology for live-view displaying or recording a moving image (HDR moving image) acquired by successively performing acquisition of composited images (HDR images) generated using this HDR compositing is also known. Because a plurality of images shot at different start timings and end timings are composited so as to generate one image, generation of the HDR moving image is likely to be influenced by change in the angle of view, camera shake or the like, and there are cases where the generated composited image is blurred. In order to address this, Japanese Patent Laid-Open No. 2014-14069 proposes a technology for suppressing blurring in a composited image during an optical zoom operation when shooting an HDR moving image.
Meanwhile, during live view display, a portion of an image is magnified and displayed in order to check the focus state. However, when magnifying the portion of the image, there are cases of display in which the focus check is difficult to perform due to a blown-out highlight state or the like, depending on the set shooting condition or the brightness of the object at the position to be magnified. To address this, Japanese Patent Laid-Open No. 2013-162420 proposes a technology for making it easy to check the focus state during live view display by providing an exposure control unit for magnification display and changing the image quality of the magnification display.
However, the above conventional technology is a technology for resolving image blurring during an optical zoom operation by outputting a non-composited image instead of an HDR image while changing the zoom magnification, and is not intended to resolve image blurring in magnification display during live view display. Moreover, the above conventional technology is a technology for changing the image quality in the magnification display during the live view display regarding a moving image that does not contain composited images, and magnification display while shooting a HDR moving image is not considered. Therefore, image blurring can occur during the magnification display, and moreover, the cost can increase because the exposure control unit dedicated to the magnification display is required.